Why would a man, respected as a writer and as a (sometimes reluctant)
pillar of the establishment, risk ridicule by embracing spiritualism
and championing the existence of fairies? Death, as the Oxford
Dictionary of National Biography puts it, was an “unobtrusive
but lifelong companion” for Doyle. The deaths of close friends
and family affected him deeply, as evidenced by the fixation
with death which runs through much of his fiction. But it was
the deaths of his son and his brother, together with the mass
slaughter during the Boer War and the First World War, which
seem to have had a mind-altering effect on him.

Spiritualism, the continued existence of loved ones on a different
plane, separate but able to communicate, offers an obvious source
of comfort to those who grieve. If all religion could be said
to be the triumph of belief over provable fact, the incentive
to suspend disbelief must be that much bigger when the apparent
reward can be enjoyed, not in an afterlife yet to come, but
immediately. If the loved one continues to speak to you, albeit
through a medium, the pain of loss is lessened or, perhaps,
soothed away completely.

Given the vigour with which Doyle pursued his other preoccupations
-- letters to the Editor of The
Times reveal his strongly-held views on everything from
the conduct of the Boer War to the advantages of a Channel Tunnel
-- it is not surprising that, having been won over to a belief
in the spirit world, he should become a crusader for spiritualism
and a foe of mockers (of whom there were many).

Doyle devoted the last 11 years of
his life to writing about spiritualism
and communication with the dead.

When the Fox family, residents of New York state, engineered
elaborate manifestations of ghostly interventions, and then
confessed to the deceit, Doyle refused to accept the confession.
When Harry Houdini systematically demonstrated his own “mediumistic”
fakery, and condemned the tricks of others, Doyle joined those
who continued to uphold spiritualist powers, including those
of the self-exposing Houdini himself! (Their shared talent for
publicity may have been the cement in a friendship which outlasted
their disagreements.)

Photo of Elsie with a gnome appears in
Doyle's The Coming of Fairies

But Doyle’s defence of two Yorkshire girls and their
pictures of gambolling fairies is probably the most extreme example
of his child-like acceptance of what today seems like laughably
amateurish attempts to trick the world. In 1917, Elsie Wright, aged
16, and Frances Griffiths, aged 10, produced a series of photos
showing them having a lovely time in the garden with fairies dancing
for their enjoyment, playing musical instruments and even, in one
case, stepping on to Elsie’s skirt.

The fact that the fairies’ wings didn’t flutter even when
they were apparently flying, and the obvious lack of anything
approaching a third dimension to the fairy cut-outs, was not
a problem for those who wished to believe, including Doyle.
To be fair, he was supported in his acceptance of the girls’
story by photographic experts who gravely opined that the pictures
were genuine - and in a sense they probably were. There was
no need to resort to double exposures if all you need were some
cardboard fairies and a box camera. Doyle hungered for spiritual
nourishment, and when his repast was threatened he strongly
fought his corner. He gathered any evidence he could find (or,
at least, convince himself that he had found), incorporating
his thoughts and his findings in his book, The Coming of the
Fairies. Many found his arguments compelling and were grateful
for the ratification of their views by such an august figure
as Sir Arthur Conan Doyle. Others, including his literary contemporaries
(and rivals), derided him.

But it is hardly surprising that a man who had achieved success
by a combination of talent for writing and talent for self-promotion,
should use these strengths to fight for a cause he needed every
bit as much as it needed him. And as to his credulity, as he
said through his principal mouthpiece (Holmes), “… when you
have excluded the impossible, whatever remains, however improbable,
must be the truth.”

-David Oldman

Spiritualism related work by ACD includes:

The New Revelation (1917)
The Vital Message (1919)
Spiritualism and Rationalism (1920)
The Wanderings of a Spiritualist (1921)
The Evidence for Fairies (1921)
Fairies Photographed, Doran (1921)
The Coming of the Fairies (1922)
The Case for Spirit Photography (1922)
The Spiritualists' Reader, Two Worlds, (1924)
Survival (1924) Doyle's contribution also published separately
as:
Psychic Experiences (1925)
The History of Spiritualism, Vol. 1 & Vol. 2 (1926)
Pheneas Speaks: Direct Spirit Communications in the Family
Circle (1927)
The Roman Catholic Church: A Rejoinder (1929)
The Edge of the Unknown (1930)